Windows/Mac/Linux (Firefox): Web-based instant messaging service Meebo connects to any and every IM chat client you can shake an avatar at, and now the popular in-browser chat application integrates tightly with your Firefox sidebar with the new Meebo Firefox extension. The extension supports visual IM notifications and drag and drop link and image sharing directly from web sites in addition to other already existing Meebo features—including file sharing. There really aren't any robust, fully cross-platform chat applications out there (though there are a few great platform-specific apps), but with this new Firefox extension, Meebo is getting close.

After you install, you can either sign in to accounts individually or sign in to your Meebo account, which holds all of your different account credentials so you can sign in to multiple IM accounts at once.

Once connected, you've got a simple contact management pane in the sidebar that you can view or collapse easily. You can even drag web content onto contact names to automatically open a new IM and share the link or image. In the meantime, your IM conversations all take place inside a Meebo tab, which is automatically opened when you sign in. The Meebo extension is free, should work wherever Firefox does. I know there are tons of Meebo fans out there, so let us know how the new extension is working out for you in the comments.

Reader Brett writes in with an interesting observation about his shared iTunes library, which he plays from his laptop and his desktop:

Previous to the latest update of iTunes, I could only have one installation of iTunes running at a time—either the desktop would work or the laptop would work. The error message was something like 'iTunes library already in use.' However, with the latest release, I've found that I can have iTunes open on both.

A quick test between my MacBook and Powerbook confirmed Brett's findings. You can play music from a single shared library on two machines simultaneously and edit ratings and playlists, which update on each computer—effectively removing the need to sync the iTunes library file manually. But it's not perfect.

Listening to the two libraries at once, for the most part, goes without a hitch. Playcount and ratings do update across libraries (eventually, if not immediately.) If you edit ratings on a song (which means iTunes has to write to its library file) and try to access that same song right away, you'll get an error like this one:

So this isn't without its choppiness or risks. I also had one machine intermittently lose track of where media files were located on the shared drive while accessing the same library. (You get the little exclamation point and iTunes says it can't find the file, and prompts you to browse for it.) In both cases, by just restarting iTunes all was well again.

Brett also says:

Prior to the latest update, I could see the iPod on my laptop when it was plugged into my desktop. Now, that no longer happens.

My tests also confirmed this, and further testing opening and closing the same library on two machines triggered another interesting error message.

Disclaimer and notes: I only tested this on two Macs, not two PC's, using the Mac's built-in file sharing. As far as I know, the iTunes library file is not compatible between Mac and PC (due to the differences in how each OS addresses file paths), so I doubt that will work at all. Brett says he had this working even when the library was shared remotely with Hamachi.

If you try this yourself, be sure to back up your iTunes library first, because having two machines write to the same file, in theory, can corrupt it. Anyone else give this a try? Let us know how it went in the comments. Thanks, Brett!

Ubuntu 7.10, the "Gutsy Gibbon" release of popular Linux distribution, is officially out this morning. You can download a live CD, request a CD through the mail, and users of 7.04 (or "Feisty Fawn") can upgrade. Check out our screenshot tour of Gutsy to see what's new and improved. Ubuntu 7.10 is, of course, completely free, and runs on PCs (and Macs) with 32- or 64-bit Intel or AMD processors.

Quick: What's the difference between putting your PC in Hibernate or Standby mode? Yeah, we weren't sure either. Luckily the Productivity Portfolio weblog schools us on the finer details of Windows XP power schemes. Using Standby:

Your machine recovers quickly as your data is stored in RAM. The slower part is waking up the peripherals. Although your machine is in "standby" the power has been cut to items such as your hard drive and monitor. You're running your machine in a very low power mode, but it is still on. This mode can be useful if you're on a notebook and need to conserve your battery while you step away.

With Hibernate:

The big difference is that your PC has shut down and is not pulling power. Another difference is that your data is saved to your hard disk and not RAM. This makes it a safer, but slower option for shut down and resume.

Not all PCs have the capability and are configured to Hibernate. If yours is, to see the Hibernate option on your XP shutdown screen, hold down the Shift key when you shut down.

One of the best tools for fine-tuning Windows XP is the free TweakUI PowerToy utility from Microsoft. TweakUI digs deep into Windows' settings and can customize its behavior dozens of ways, from how many icons appear on the Alt-Tab dialog to Explorer context menu choices to what your program shortcuts look like. TweakUI's been around forever and we've mentionedithere and there throughout the years at Lifehacker, but it's high time we gave it the full walk-through it deserves. After the jump, take a gander at 15 useful adjustments you can make to your XP system with TweakUI.

Looks like a little freezer time can save more than just a dead hard drive: according to this video over at Metacafe, you can also revive a dead laptop battery by freezing it for 14 to 15 hours. We haven't tried this trick ourselves, but a little cursory research using The Google shows that it's been discussed and recommended online before. Anyone else have luck (or know the science behind) freezing a battery back to life? Let us know in the comments.

Booting Linux from an external drive with the applications and settings of your choice has never been easier after this week's release of Puppy Linux 3.0. Like Damn Small Linux, Puppy is small enough to fit on a USB thumb drive, and like Knoppix , you can boot it from CD. Puppy can also add your favorite open source applications to the desktop and save multiple user profiles back to your writable CD or thumb drive, too. Let's take a look at how you can take your operating system, apps, data and user settings to go with Puppy Linux.

What You Can Do with Puppy

Compute on a machine without leaving a trace—like browser history, cookies, documents or any other files—behind on the internal hard drive

While there's a wide range of Linux live distro's available, Puppy Linux is a fantastic option which offers a full computing environment with rich graphical apps like the Mozilla Seamonkey suite, Word and Excel equivalents, calendar, chat and photo editors, too.

Set Up and Boot Puppy Linux for the First Time

First burn the Puppy .ISO image to CD using ISO Recorder. (With ISO Recorder installed, just right-click the disk image to copy to CD.) Once your Puppy Linux CD is written, leave it in your CD drive, shut down your computer and restart. If your computer is set to boot from CD, Puppy Linux will start. (See step 2 listed here for more info on setting your computer to boot from CD if Windows starts up again, even with the Puppy CD inserted.)

When Puppy boots you'll have to answer a few questions before you see a desktop: what keyboard layout it should use (most likely the first choice, U.S.), and what video resolution it should use based on your video card and monitor. The video setting can be a bit hit or miss, but you can test the various options to find the one that works. (While I didn't have any trouble on a 5 year old Dell PC, at least one Lifehacker reader had a bit of trouble.) Once you start up X (Puppy's windowing system), you'll get a desktop that looks like this (click to enlarge):

Puppy doesn't automatically mount your thumb drives or connect to the network, you have to do that for it. As the instructions embedded on the desktop say, click on the Connect icon (just once, not twice!) to get your internet access set up. Here's what that looks like:

Here you see Puppy recognizes my one network interface—in this case, an Ethernet connection, eth0. Clicking on that and hitting the "Auto DHCP" button got me online immediately, and I could use the built-in browser and chat client.

You don't have to set up your network connection every time you boot Puppy. Once you've acquired an IP address, Puppy will ask you if you want to save the settings for your next session. (More on session info saving below.)

The other thing you'll want to do is mount your thumb drive, which Puppy also does not do by default. Click on the Drives icon, then select your flash drive (which should be plugged in, if not, do so and then click Refresh).

Save Your Puppy Linux Settings to Writable CD or USB Drive

Once you've got your initial setup complete, shut down Puppy to save your settings either to your USB drive—or if you left your CD-R session open, to CD. When you shut down Puppy it will ask you if and where to save your session, which you'll also be able to give a custom name.

Next time you boot up Puppy with the USB drive plugged in (or from that writable disk), it will automatically detect your session settings and the desktop will no longer have the initial run wallpaper included. It will look more like this (click to enlarge):

From here you can further customize your Puppy session (use multiple workspaces, set your desktop background, timezone, shortcuts, etc.) To save your session at any point to thumb drive, click once on the "Save" icon.

Add Applications to Puppy Linux

Puppy comes with a stunning array of rich desktop applications to start with (do explore the menu to check 'em out), but not all of them might be familiar to you. Luckily you can add your familiar favorites using Puppy's package manager, its answer to Windows Install Wizard. From the Menu's Setup area, launch the PETget package manager and pick and choose the apps you want to add to puppy. (Click to enlarge screenshot):

Here you can see I'm adding Firefox, Thunderbird, the Gimp, OpenOffice.org and an interesting looking money manager called PuppyMoney. It's a virtual software buffet!

Booting and Saving to Only a USB Drive

Sadly my old PC doesn't have the ability to boot from a USB flash drive, but yours might. To ditch the optical disk entirely, install Puppy to a USB drive using the universal installer (located in the Menu's Setup area.) There you can install Puppy to the media of your choice:

More Puppy Help and Resources

While I've only scratched the surface of getting started with Puppy, to dive in deeper, check out the copious documentation and tutorials available, like:

Gina Trapani, the editor of Lifehacker, likes getting her Linux to go. Her weekly feature, Geek to Live, appears every Friday on Lifehacker. Subscribe to the Geek to Live feed to get new installments in your newsreader.

Not interested in upgrading to Windows Vista? No problem. ComputerWorld has written up a how-to detailing exactly what you need to to keep Windows XP running smoothly - with a few of the best Vista goodies mixed in.

I've upgraded to Vista on one machine but I'm staying with XP on my other one, so this article came just in time for me. Tips include how to get Vista's security upgrades in XP, how to tweak XP's settings for maximum performance, and how to get that oh-so-lovely look of Vista on an XP machine. How about you - if you've decided not to upgrade, please share how you're configured your machine to wait until the next inevitable Windows release.